Adhesion preventing agent for catheters and the like



J. M. AUZIN 2,390,070

ADHESION PREVENTING AGENT FOR CATHETERS AND THE LIKE Dec. 4, 1945.

2 Sheet s-Sheet 1 Original Filed May 51, 1941 vezz $0 7 94+ flzzomgy J. MQAUZIN Dec. 4, 1945.

ADHESION PREVENTING AGENT FOR CATHETERS AND THE LIKE 2 Sheets-Sheet 2 v Original Filed May 31, 1941 Patented Dec. 4, 1945 ADITESION PREVENTING AGENT FOR CATHETERS AND THE LIKE John M. Auzin, Warwick, R. 1., assignor to Davol Rubber Company, a. corporation of Rhode Island Original application May 31, 1941,.Serial No.

Divided and thlsapplicatlon August 7 24, 1943, Serial No. 499,863

3 Claims.

The invention consists of a novel adhesion pre-- venting means more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more specifically defined in the claimsappended thereto.

In the drawings:

Fig. 1 is a view, partly broken away, of an inflatable catheter constructed in accordance with my invention, the catheter being deflated;

removed fromthe pin before the end of the tube is pushed over it. The dipping is continued, a small drop of coloring matter being applied after each dip to mark the end of the tube 2|, in order to mark the place for making the desired connecting opening. When the catheter has been sufiiciently built up, the form and the catheter are placed in. a cold water bath, a hole being burned through the wall at the colored spots to make a connecting opening 22 to the interior of the tube it, the preferred spacing being just below the tube end, to avoid making the opening through the marking The form and the catheter are removed from the cold water bath, surface dried with cheese cloth or the like, and

- the region A, see Fig. 3, where the balloon is to Fig. 2 is an elevation, partly broken away, of

the catheter former;

Fig. 3 is a fragmentary view showing the lower end of a partially formed catheter;

Fig. 4 is a view similar to Fig. 3, showing the application of an adhesion preventing material;

Fig. 5 is a fragmentary view, partly in section, showing the lower end of the catheter after final dipping; and

Fig. 6 is a section on the line 6-6 of Fig. 5

Referring to the drawings, the catheter ill includes a tubular section H and an inflatable balloon section l2, preferably made as an integral one piece device, the tubular section having a central longitudinal flow passage l3 terminating at the tip end l4 and having one or more fluid ducts l5 through the section wall l6 as shown in Fig. 1, the wall i6 having a longitudinal passageway H which terminates in a wall recess 18 formed between the balloon section and the wall.

The catheter is preferably formed as a onepiece article by dipp a former is, see Fig. 2, having a longitudinal groove 20. This former is dipped in rubber solution, either natural or synthetic, until a. thin rubber layer is obtained. Then a rubber tube 2! is coated with rubber cement, and is inserted in the grooved portion over the formed layer; the tube is bevelled oil? at the lower end, the opening therein being plugged with a drop of rubber, preferably latex. The upper end is inserted over a pin I90 on a funnel forming arm use which is secured to and is part of the end of the former l9, this pin sealing the lower end so that no rubber can enter the tube, and facilitating the formation of an integral funnel end for the upper end of the inflation tube. Since the pin has an initial rubber coat as the result or the first dippings, this coat is be formed, is then treated with a local adhesive preventing agent, indicated by the reference numeral to surface treat this region and prevent adhesion of later dips thereto; the local agent is then washed off, and the catheter is placed back. in the cold water bath. This treatment leaves a surface area. which is clean, and yet prevents adherence of, the subsequently dipped coatings, The cold water bath has the effect of preventing uneven drying of the rubber, thus facilitating the production ,of a uniform thickness for the balloon which is subsequently formed. Each catheter is taken out of the cold water bath, and surface dried with the cheese cloth; the connecting opening or hole 23 is closed or plugged with a. drop of latex and the catheter is again dipped, the resultant layer or layers thus forming a balloon at the region A, as there is no adhesion with the previous layers of rubher. If desired, a layer of rubber cement may be applied at each end' of the region A, to ensure a. perfect adhesion and an integral joining.

The completed catheter is air dried, stripped from the form, and is put in a drying tray and additionally dried. It is then put in a hot water bath, approximately C., to leach out water so1- uble proteins from the rubber; then the balloon is loosened by pumping air or water under slight pressure into the passageway ll, and the outer end of the p s ageway H is p ug ed so as to keep the'balloon slightly distended. The inflation of the balloon removes the latex or rubber drop or plug from the connecting hole 22, the plug adhering to the inner wall of the balloon, and clearin the passageway ill.

The catheter is slowly dried for a long period preferably under natural conditions, and is then vulcanized to be ready for use.

Although any adhesion'preventing agent may be used to coat the section A before dipping to form the balloon, I prefer bromine as the chemical agent, as it has a tackiness removing action on the rubber. Bromine solution may be used, but I have found that the solution has a tendency to creep beyond the desired limits, and I therefore use the bromine in the form of a paste, obtained by mixing bromine solution with a neutral powder such as Dixie clay. Another local treating agent is bleaching water to which a little sulphuric acid has been added; this is preferably also mixed with a neutral powder such as Dixie clay, which is inert to rubber and does not react with rubber, I

to form a paste. 4

- While I have described specific means for preventing local adhesion during the formation of a balloon for a catheter, it is obvious that the principle may be used for other types of catheters and other forms of rubber articles, having inflat- I steps of treating a rubber base with a paste containing a mixture of bromine solution and a neutral powder which is inert to and does not react with rubber, and coating the treated base with rubber in solution.

I JOHN M. AUZIN. 

